Summary Wound healing is vital for the health and survival of multicellular organisms in their natural environment, and is of general biomedical significance. Skin wound healing in vertebrates involves the coordinated action of multiple tissues and cellular processes. Numerous signaling pathways have been implicated in the detection of and response to damage, yet major gaps exist in our knowledge of how such signals are triggered, integrated, and how they direct the diverse outcomes in wound repair in vivo. The overall goals of this project are to use the nematode C. elegans as a model for genetic and cellular analysis of epidermal wound repair. The adult C. elegans epidermis is a simple barrier epithelium that efficiently repairs puncture or laser wounds. Wounding triggers a set of epidermal responses including cytoskeletal rearrangements and induction of antimicrobial peptide transcription. Previous studies revealed a key role for calcium signaling in driving the cytoskeletal rearrangement in wound healing. This project will explore novel signaling mechanisms in C. elegans wound responses. We propose two specific Aims. In Aim 1 the roles of mitochondrially generated reactive oxygen species (ROS) in wound-triggered signaling will be tested critically using a combination of candidate gene testing and forward genetic screens. Mutants displaying constitutively activated wound responses provide genetic mimics of the wound response and have allowed large-scale genetic screens to identify potential components of wound repair pathways. Such screens have revealed unanticipated roles for the microtubule cytoskeleton in wound repair. In Aim 2 the roles of microtubule dynamics regulators in wound repair in vivo will be assessed. The results of this research will lead to a better understanding of how epithelial repair processes operate in vivo to allow organisms to survive life threatening physical injuries. Key wound triggered signals such as calcium and ROS may play conserved roles in wound healing in many organisms, and results from these studies could inform our understanding of mechanisms of wound repair in mammals and humans